PRECIOUS METALS CHEMICAL & COMPOUNDS

AQUA REGIA : A mixture of three parts hydrochloric acid and one part nitric acid used to test the purity of gold and platinum. The mixture is one of the few chemicals that can dissolve those metals.

ROUGE : An abrasive compound used with a buffing wheel to polish metals. Rouge is graded by the size of the abrasive, from very course to very fine (even though none of the grit is as large as any fine sandpaper), and each of the grades in between have different uses. For cutting down a rough surface (or removing heavy oxidation), Brown Rouge (also called Red Rouge) is considered a semi-aggressive primary compound because it contains large grains of abrasive (even though they are so small they can only barely be felt when rubbing the compound between your fingers). Brown Rouge is used for the first step in the polishing process for unfinished metal. Some metal-smiths only use Brown/Red rouge. Green Rouge is finer yet, and is sometimes used for a second polishing. White rouge contains the very finest abrasive and is used for the final polishing to produce a very high shine.

JEWELRY INDUSTRY TABLES, CHARTS AND MEASUREMENTS

Table 1

Fineness of Gold in Karats

United State Markings

Parts Gold

Gold %

European Markings

24K

24/24

100%

1000 or 999

22K

22/24

91.7%

916 or 917

18K

18/24

175.0%

750

14K

14/24

158.3%

583 or 585

10K

10/24

141.7%

417

Table 2

Conversion Table - Gauge to Inches and Millimeters

Gauge Size

10

12

14

16

18

20

22

24

26

28

30

Diameter in inches

.1019

.0808

.0641

.0403

.0508

.0320

.0253

.0201

.0159

.0125

.0100

Diameter in mm

2.588

2.05

1.63

1.29

1.02

.813

.643

.511

.404

.320

.254

 

 

 

Table 3

Conversion From Troy Weight To Avoirdupois (U.S.) To Metric Weight

 

TROY (t)

AVOIRDUPOIS (Av)

METRIC

Pound (Ib t)

1 lb t

0.82291b

0.3732 kg

Ounce (oz t)

12 oz t

13.16570z

373.2422 gm

Pennyweight (dwt)

240 dwt

210.6514 dr

373241.7216 mg

Grains

5760 grains

5760 gr

Table 4

Alloy Composition of Gold Colors

Color

Alloy %

Color

Alloy %

Yellow Gold (22k)

Gold 91.67%
Silver 5%
Copper 2%
Zinc 1.33%

Deep Green Gold (18K)

Gold 75%
Silver 15%
Copper 6%
Cadmium 4%

White Gold (18k)

Gold 75%
Palladium 10%
Nickel 10%
Zinc 5%

Pink Gold (18K)

Gold 75%
Copper 20%
Silver 5%

Green Gold (18k)

Gold 75%
Silver 20%
Copper 5%

Light Green Gold (18K)

Gold 75%
Copper 23%
Cadmium 2%

Gray-White Gold (18k)

Gold 75%
Iron 17%
Copper 8%

Rose Gold (18K)

Gold 75%
Copper 22.25%
>Silver 2.75%

Soft Green Gold (18k)

Gold 75%
Silver 25%

Red Gold (18K)

Gold 75%
Copper 25%

White Gold (18K)

Gold 75%
Platinum 25% or
Palladium 25%

Blue-White or
Blue Gold (18k)

Gold 75%
Iron 25%

Purple Gold

Gold 80%
Aluminum 20%

Table 5

Suggested Necklace, Bracelet and Anklet Lengths

Type of Jewelry

Average Adult

Length How to Measure for Extra Large or Small Sizes

Bib Multi-Stranded

12-13 up to 20"- 23"

The first strand is usually choker length, and each strand below it longer by approx. 1"-2"

Collar Multi stranded

(all strands same length)

12"-13"

Neck Circumference + 1"

Choker

14" to 16"

Neck Circumference + 1.5" to 2.5"

Princess Length

17" to 19"

Adjust to fit customer; usually worn with higher necklines

Graduated strand

17" to 19"

Largest bead in center of necklace, gradually decreasing in size toward clasp.

Matinee

20" to 23"

Adjust to fit customer; usually worn for casual daytime wear

Eyeglass necklace

27"

Adjust to fit customer preference

Opera

30" to 35"

Adjust to fit customer; sometimes doubled to be worn as a choker

Rope

40" -45"

Adjust to fit customer preference

Lariat Both ends left unattached, or one end with a dangle and the other with a loop

At least 48"

Customer preference - no set standard

Bracelet, Closed Bangle

Standard: Approx. 6.5 mm ID
Approx. 21 mm circumference

Designed to slip over a slender adult hand; adjust for size by measuring the circumference of the hand at the widest point when hand is held in the position for putting the bangle on, add 10mm.

Cuff Bracelet, Hinged Bangle

Standard: Approx. 6 mm ID

Measure the wrist at the widest point where the cuff will rest, add about 5mm for comfort, unless the wearer wants it snug.

Anklet

Sm: 6.5"
Med: 8"
Lg: 9.5"

Measure circumference of ankle and add approx. 1/2 inch.

ADDITIONAL USEFUL TABLES

Recommended Metal Gauge (Thickness)
It is recommended that sterling silver materials should be approximately 10% to 25% thicker than the same materials in14K gold to get comparable strength characteristics.

For

Use

Rings and weddings bands

16 gauge for women's rings
14 gauge for men's rings

Bezel material

32,30,28 gauge

Ear wires

22, 20 gauge

Bracelets

18, 16, 14 gauge

Repousse

24, 22 gauge

Jump rings

22, 20, 18 gauge

Brown & Sharpe Gauge for Thickness in Inches and Millimeters

Gauge

Inches

Millimeters

Gauge

Inches

Millimeters

0

.325

8.26

20

.032

.812

2

.257

6.54

21

.028

.723

4

.204

5.19

22

.025

.644

6

.162

4.12

23

.023

.573

8

.128

3.26

24

.020

.511

10

.102

2.59

25

.018

.455

12

.081

2.05

26

.016

.405

13

.072

1.83

27

.014

.360

14

.064

1.63

28

.013

.321

15

.057

1.45

29

.011

.286

16

.051

1.29

30

.010

.255

18

.040

1.02

32

.0080

.2019

19

.036

.912

34

.0063

.1600

This chart is a relative measure for the workability of different alloys for wire wrapping. Approximately Ultimate Tensile Strength (psi shown in thousands)

14Kt Yellow Gold

Yellow gold-filled

(12/20 & 14/20)

Sterling Silver

Fine Silver

Rich Low Brass

Pure Copper

Common Term

Brown & Sharpe Numbers

Reduction in Area of wire

69

40

40.5

26

37

33

Soft (annealed)

0

0%

88

50

48.5

33

49

40

1/4-hard

1

21%

98

60

54

41

56

45

1/2-hard

2

37%

110

70

60

43

62

50

3/4-hard

3

50%

124

75

66.5

45

68

55

Full hard

4

60%

145

90

89

51

82

66

Spring hard

8

84%

Pt.

FG

22K

18K

14K

10K

9K

FS

SS

Pt

1.00

0.90

0.82

0.70

0.60

0.53

0.53

0.49

0.48

FG

1.11

1.00

0.91

0.78

0.67

0.59

0.58

0.54

0.54

22K

1.22

1.10

1.00

0.86

0.73

0.65

0.65

0.60

0.59

18K

1.42

1.28

1.16

1.00

0.85

0.76

0.75

0.69

0.68

14K

1.66

1.50

1.36

1.17

1.00

0.89

0.88

0.81

0.80

10K

1.88

1.69

1.54

1.34

1.14

1.01

1.00

0.93

0.92

9K

1.90

1.71

1.56

1.34

1.14

1.01

1.00

0.93

0.92

FS

2.04

1.84

1.68

1.44

1.23

1.09

1.08

1.00

0.99

SS

2.07

1.87

1.70

1.46

1.25

1.11

1.09

1.01

1.00

Precious Metals Comparison Chart
Using Platinum as the Base Standard of 1.00

Abbreviations used in above Chart

Pt

Platinum

FG

Fine Gold

22K

22 Karat Gold

18K

18 Karat Gold

14K

14 Karat Gold

10K

10 Karat Gold

9K

9 Karat Gold

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Sterling Silver Round Wire

Gauge

Width

Ft./ln. per Oz

Oz per Ft

26

.015

75.0'

24

.020

48.0'

.021

22

.025

31.0'

.033

21

.028

24.0'

.042

20

.032

19.0'

.053

18

.040

12.0'

.084

16

.051

7.5'

.133

14

.064

4.66'

.212

12

.081

3.0'

.337

10

.102

22.0"

.536

8

.128

14.5"

.852

6

.162

9.0"

1.333

4

.204

5.5"

2.182

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Sterling Silver Half Round Wire

Gauge

Width

Ft./ln. per Oz

Oz per Ft

24

.020

96.00'

.010

22

.025

62.00'

.016

21

.028

50.00'

.020

20

.032

38.00'

.026

18

.040

24.00'

.042

16

.051

15.00'

.061

14

.064

9.50'

.106

12

.081

6.00'

.168

10

.102

3.75'

.280

8

.128

2.33'

.424

6

.162

1.50'

.667

4

.204

11.0"

1.090

2

.257

7.0"

1.714

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Sterling Silver Square Wire

Gauge

Width

Ft./ln. per Oz

Oz per Ft

24

.002

36.0'

.028

22

.025

22.0'

.045

21

.028

20.0'

.053

20

.032

14.0'

.071

18

.040

9.5'

.107

16

.051

7.5'

.133

14

.064

4.66'

.212

12

.081

3.00'

.337

10

.102

22.0"

.536

8

.128

14.5"

.852

6

.162

9.0"

1.333

4

.204

5.5"

2.182

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Sterling Silver Triangle Wire

Size

Base x Height

Length per Oz

Oz per Ft

1

.380" x .225"

3.75"

3.160

1.5

.325" x .200"

45/8"

2.590

2

.258" x .160"

75/16"

1.640

3

.215" x .097"

l' 3"

0.796

4

.175" x .090"

l' 7"

0.644

5

.156" x .111"

l' 5"

0.705

6

.122" x .095"

l' 11"

0.519

7

.103" x .081"

2' 6"

0.399

8

.080" x .064"

4' 1"

0.245

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Sterling Silver Double Half Round Wire

Gauge

Height x Width 1/1000"

Length per Oz

14

.033" x .173"

3.42 ft.

12

.040" x .162"

2.77 ft.

10

.051" x .204"

1.83 ft.

6

.081" x .257"

10.5 in.

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Sterling Silver Low Dome Wire

Number

Base x Height 1/1000"

Length per Oz

Oz per Foot

5

.170" x .040"

33.0"

0.39

4

.232" x .072"

13.75"

0.90

3

.412" x .062"

9.50"

1.15

2

.515" x .072"

7.0"

1.75

1

.608" x .077"

6.0"

2.00

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Gold-Filled Round Wire

Gauge

Width

Feet Per Ounce

18

.040

13.96

20

.032

21.68

21

.028

28.06

22

.025

35.55

24

.020

56.33

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Gold-Filled Half Round Wire

Gauge

Width

Feet Per Ounce

18

.040

27.91

20

.032

42.87

21

.028

59.82

22

.025

66.79

24

.020

112.66

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Gold-Filled Square Wire

Gauge

Width

Oz/Foot

Length/Oz

14

.064

.232

51 3/4"

16

.051

.136

88"

18

.040

.092

128"

20

.040

.058

207"

21

.028

.044

273"

22

.025

.036

331"

24

.020

.024

504"

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Gold-Filled Bezel Wire

Gauge

Width

Ounce/Foot

Inch/Oz

30

1/8"

.069

74"

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Copper Round Wire

Copper wire is relatively in expensive and is usually sold in coils or rolls of a specified length.

Gauge

Width

Feet per Pound

12

081

50'

14

.064

80'

16

.051

126'

18

.040

199'

20

.032

315'

22

.025

501'

24

.020

793'

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Bronze Square Wire (soft)

Gauge

Feet Per Pound

10

25.20'

12

40.16'

14

66.14'

16

108.66'

18

169.29'

20

264.57'

22

433.86'

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Bronze Round Wire (soft)

Gauge

Feet Per Pound

8

20'

10

32'

12

51'

14

84'

16

138'

18

215'

20

336'

22

551'

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Brass Round Wire (soft)

Gauge

Feet Per Pound

8ga

20'

10ga

32'

12ga

51'

14ga

84'

16ga

138'

18ga

215'

20ga

336'

22ga

551'

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Brass Square Wire (soft)

Gauge

Feet Per Pound

10

25.20

12

40.16

14

66.14

16

108.66

18

169.29

20

264.57

21

395.00

22

433.86

24

750.00

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Nickel Silver Round Wire (soft)

Gauge

Feet Per Pound

8

20'

10

32'

12

51'

14

84'

16

138'

18

215'

20

336'

22

551'

 

 

 

 

 

 

 

 

 

 

 

WIRE LENGTH PER OUNCE and WEIGHT PER FOOT - Nickel Silver Square Wire (soft)

Gauge

Feet Per Pound

10

25.20'

12

40.16'

14

66.14'

16

108.66'

18

169.29'

20

264.57'

22

433.86'

No matter how you shape it, wire sculpted jewelry is here to stay. The more you know about your medium of choice, wire, the better your work will become.